Method of making dentures



Jan. 22,1929; 11,699,859

" 'J. C. SCHWARTZ METHOD OF MAKING DENTURES Fi le'd Sept 13, 1926 2Sheets-Sheet 1 [N WEN TOE "7 7'0 ENE v Jan. 22, 1929. 1,699,859

.LC. SCHWARTZ METHOD OF MAKING DENTURES Filed Sept. 13. 1926 '2Sheets-Sheet 2 Q I i x 1 1 13* f 7 /4 J5 [NVEMTO/P Jacob ffia/wmr/z 65VM QT TOENJ: Y

Patented Jan. 22, 1929.

UNITED STATES PATENT OFFICE.

JACOB C. SCHWARTZ, OF ST, LOUIS, MISSOURI; IBERTHA SGI'IWARTZAND MER-CANTILE TRUST COMPANY EXECUTORS OF JACOB C. SCHWARTZ, DECEASED.

METHOD OF MAKING IDENTURES.

Application filed September 13, 1926. Serial No. 135,143.

This invention relates generally to prosthetic dentistry and, moreparticularly, to acertain new and useful improvement in methods ofmaking dentures.

llriefly, according to the present-day practice of constructing sets ofartificial or false teeth, commonly known as dentures, so far as 1 amaware, the several teeth are initially mounted to correct alignment andocclusion in plastic wax. The teeth, as so mounted, are then placed inasectional molding-flask, and liquid or fluid plaster-of-Paris poured into [ill the mold and on hardening form a socalled intermediate base forthe teeth. The flask is thereupon closed, and the plaster permitted tosetand harden. To now soften for removal the initial wax'base, the flaskor mold is immersed in hot water which effects a softening of theinitial wax base, so that it may be subsequently, and prior to rubbervulcanite packing, removed, but at the same time the plaster is so moreor less Watersoaked as to impair its rigidity and grip upon the teethfor maintaining the teeth, during the remaining denture-forming steps,in

their original alignment for perfect occlusion. Following suchWax-softening step, the flask is opened and the softened wax removed,the teeth being now supported by and set in the so relatively hardenedplaster, which thus functions as an intermediate base for the teeth.Rubber vnlcanite being now packed upon the intermediate base and aboutthe teeth, the flask is again closed and subjected to pressure tocompact the rubber vulcanite prior to vulcanization. The flask is thendisposed within a suitable vulcanizing apparatus to etl'ect thorough andcomplete vulcanization of the rubber vulcanite. Following vulcanization,the flask opened, the cast taken therefrom, and the plaster suitablyremoved, leaving the teeth set in the hardened and vulcanized rubber.which forms the final base and mounting of the teeth. During, however,such vulcanite compacting step or opera tion. due to the water-soakedcondition and hence impaired rigidity and firmness of the temporary orintermediate plaster base, the original alignment of the teeth for thedesired occlusion is very frequently so affected that the final dentureis faulty and imperfect.

My present invention has hence for its object the production, in aneconomical, etficient, and readily practiced manner, of dentures whichuniformly and substantially perfectly process of constructing the same,as hei'einafter described and pointed out in the claims.

in practicing my process or method and in the production of the denture,1 preferably employ certain relatively simple apparatus and equlpment,and in the accompanying drawings,

. Figure 1 illustrates in elevation a drysteam apparatus such as ispreferably employed in practicing my method and in the formation of mynew denture;

Figure 2 is a plan View of the several teeth as first or initially setin war: to correct occlusion and alignment.

Figure 3 illustrates a common type of molding-flask employed in theproduction ot the denture, the parts or sections of the flask beinginseparated assembling relation;

Figure 4: illustrates the several teeth as set in the intermediateplaster-of-Paris base and prior to the packing therearound of therubber-vulcanlte, sectionsof the mold being removed; y

Figure 5 illustrateapartly in elevation and partly in section, apreferred type of press and mold employed in the compacting of therubber-vulcanite of the denture prior to vulcanization; and y Figure 6shows in elevation a co-opcrating or matching pair of the finisheddentures in occludent relation.

, Referring now more in detail and by reference characters to thedrawings, the apparatus and equipment employed in the practicing ofmynew. dentures may be described as including a work-table 1, at whichvarious of the dentuieforming operations may be conveniently performed.Disposed on table 1, is an oven or dry heatchamber Qand awatercontaining receptacle or tank 3, the chamber or oven 2 and thewater in tank 3 being heated by steam or other medium furnished throughvalve-controlled piping 4 from a suitable generating-furnace 5 or othersource of supply. Preferably adjacent table 1, is a second or auxiliarytable 6, upon which is located a suitable tank 7, adapted forcooperation with Which is a flexible hose 8 having suitablesupply-connection with the piping 4 and carrying a suitablesprayingnozzle (not shown) preferably, when not in use, permitted torest within a tank or receptacle' 1'0 mounted for convenience on table1.

Now, in the formation of the dentures, the several false or artificialteeth a are first set to correct alignment and occlusion in an initialbase 6 of plastic wax or other suitable material or compound, and thewax base 6 then arranged upon a preferably rigid plaster or other hardplate 0, as shown in Figure 2.

Employing now preferably the flask or mold shown in Figure 3, which, asthere shown, is of sectional construction comprisinga main orbody-portion 11, a lid or endinember 12,and a bottom or secondend-meniher 13, the body member 11 being provided with tongues 14adapted to regis ter with slots 15 provided in the enclmembers 12 and13, theplate c and its superposed wax-base Z) and set teeth a are placedupon the one bottom member 13 and enclosed within the body-portion 11.The flask or mold is then filled with plaster-of- Paris in a liquid orfluid state, so that the ortions of teeth a protruding from the waxliaseb are entirely covered by and with the fluid plaster. The oppositeend-member 12 is now placed upon the body portion 11 and the flaskclosed. The plaster c more or less quick- 1y sets, and I might hereobserve that, in order that the matrix or hardened plaster cl, seeFigure 4, may be subsequently easily separated from the plaster or otherplate 0, a suitable separating compound may be disposed upon the initialhard plate 0. 7

As the fluid plaster hardens, it will be evident that the upper portionsof the teeth a protruding from the wax-base 6 become set in and aregripped by the plaster. Now, as I have heretofore stated, the presentpractice is to immerse the closed flask and initially setplaster-of-Paris in a tank of hot or boiling water in order to softenand in due course enable the removal of the initial wax-base b. Thisstep has been considered essential and has been standard practice, sofar as I am aware, for many years. The result of such immersion is,however, that, while the waxbase 6 is softened, the plaster-of-Parisbecomes so water-soaked that its rigidity is affected to such an extentasto lessen the firmness of its grip upon the teeth a, with the ultimateresult that the teeth of the final denture are often out of theiroriginal correct alignment for the perfect occlusion desired. In mymethod of denture production, I entirely eliminate such water-soaking ofthe plaster-of-Paris and now place the so closed mold or flask in theoven or dry heat-chamher 2, where the flask is subjected forapproximately fifteen minutes to a. baking temperature of approximately300 F. Such relatively slow baking or heating effects a softening of theinitial waxbasel but at the same time, by removing through evaporationthe surplus'moisture or water content of the plaster, thoroughly,uniformly, and completely hardens and rigidities the plaster, with theresult that the plaster firmly and tightly grips the several teeth infull accordance with their original wax-setting and is thereafterrigidly pressure-resisting. I may here state that I have found that bestresults are obtained in the employment of a baking period ofapproximately fifteen minutes at the ten1perature stated; it is to beunderstood, however, that variations in bot-h the baking period and inthe baking temperature may be effective in accomplishing my purpose. Imight ob serve, however, that too prolonged baking or too great heatmight tend to disintegrate the plaster and thus injuriously effect itsefliciency inthe performance of its functions.

Now, after such baking, the flask is taken from the oven 2 and inverted,when the one end member 12 now becomes the bottom of the flask. Theother end-member 13 is removed and therewith the hard plate 0, thesoftened wax-base 6 being then exposed. However, the teeth a are nowrigidly mounted in inverted position in the initially fluid, but nowrigidly hard plaster d, which now functions as an intermediate base forthe teeth. The flask with its contained hard plaster base (l and itsrigidly held teeth a are now dis posed within the tank 7 and subjectedto a jet of relatively high pressure steam ejected through the nozzlecarried by the hose 8, which effects through blowing and washing aremoval from the teeth a of any remaining parts or particles of theinitial wax base I) and also a thorough cleaning of the new base (Z.Imight observe here that the steam used in this step of mydenture-forming method has a temperature of preferably 800 F. and issuesfrom the hose 8 under a pressure of approximately to pounds per squareinch. The flask, so containing the base (Z and its gripped teeth a, is,immediately following such wax-removal and cleaning operation,preferably placed within the oven 2 so as to effect by evaporation theremoval of any surface moisture.

011 removal again from the oven 2, the usual rubber vulcanite in sheetor strip form is packed over the base (Z and about the protrudingportions of the teeth (a, and the flask again completed by replacementof the endmember 13 and hard plate 0. In view, however, of theinterposed rubber vulcanite, the flask will not tightly close, and tonow coinpact the vulcanite to effect a total closure of the flask forvulcanization, the flask is placed within a press of preferably the typeillustrated in Figure 5. As there shown,this press con'iprises a frame16 having a base 17 upon which the flask may rest. Mounted forrotatorymovement int-he frame 16, is a thread- Ill] 22 upon the flask.

ed rod 18 carrying at its one or upper end a hand-wheel 19. At its otheror lower end, the rod 18 has a ball-joint connection, as at 20, with apresser-plate 21. The flask being interposed between the base 1? and thepresser-plate 21, the presser-plate 21 is adapted for co-operation witha second or auxiliary presser-plate 22 seated upon the flask, the plates21, 22 having means co-acting therebetween, as, for instance, dowels 23upon one plate and registering slots 2% upon the other plate to receivethe dowels so that vertical alignment of the plates is assured. A coilspring 25 is interposed between the plates for normally evenly spacingthem apart, the spring having its ends seated in recesses providedtherefor in the plates 21, 22, as shown, the ball-joint 20 providingsubstantially a universal movement of the presser-plates and insuring afirm uniform pressure of the plate The hand-wheel 19 is now actuated tocompact to as great an extent as possible the rubber vulcanite. Suchoperation, however, is rarely, if ever, capable of completely closingthe flask, due to the interposed thickness of the vulcanite, and thepress with the so-contained partly open flask is hence now placed withinthe tank 3, with the flask out of direct contact with the water therein,but close enough thereto to be heated by the hot vapor arisingtherefrom. Such vapor, in turn, effects a softening of the rubbervulcanite, whereupon, without additional operation of the hand-wheel 19,but through the spring pressure exerted through and by the spring 25,the flask is gradually and automatically closed as the rubber vulcaniteso softens and packs into place. I might say that such reheating andspring closing operation usually consumes from fifteen to twentyminutes.

After the flask is thus entirely closed, the press is taken from thetank 3 and the flask removed from the press and placed within a suitablevulcanizing apparatus of any stand ard type, not here shown, to effectvulcanization of the rubber vulcanite, which ultimately becomes thefinal and permanent base for the teeth a and the plate proper of thedenture. in due course, the flask is taken from the vulcanizingapparatus and opened and the plaster-oflaris base or cast (Z suitablyremoved from around the teeth, when the several teeth a now appear inthe finished denture firmly and solidly mounted within the hardvulcanized rubber e in exactly the alignment and occlusion as wheninitially mounted in the soft wax base 5.

Thus by my process I entirely eliminate mushy, water-soaked plaster andobtain firm, hard, pressure-resisting plaster that yields uniformlyperfect dentures, in the production of which also the rubber is notcooked to a crusty, flaky consistency, the rubber vulcanite beingcompacted with forceful, evenly distributed pressure and, aftervulcanization, the rubber retaining its life, resiliency, and toughnessthat enables the denture to withstand hard knocks and obviates breakageand repairs. An d by my process, the dentures are uniform and preciseand in correct articulation and occlusion, and further treatment andalterations of the dentures when fitting the same into the month are.reduced to a minimum.

It will be evident that various modifications may be made in mydentureforming method without departing from the nature and spirit of myinvention.

Having thus desc ibed my invention, what I claim and desire to secure byLetters Patent is: i i i 1. Those steps in the construction of den tureswhich consist in subjecting the waissct and plastei covered teeth to dryheat for softening the wax and drying and hardening the plaster, andthen blowing off the softened wax. a

2. Those steps in the construct-ion of dentures which consist insubjecting the wax-set and plaster-coveredteeth to heat within oven forsoftening the wax and drying and hardening the plaster in grippingengagement with the teeth, and then blowing off the softened wax.

3. Those steps in the construction ofdentures which consist in bakingthe wax-set and plastcncovered teeth within an oven for softening thewax and drying and hardening the plaster in gripping engagement with theteeth, and then blowing off with dry steam the softened wax.

l; The method of constructing dentures which includes mounting the teethupon an initial wax base, covering the mounted teeth and base with fluidplaster, subjecting the whole to heat in an oven to soften the wax andrigidly harden the plaster grippingly about the teeth, blowing off thesoftened wax, packing rubber vulcanite on the hardened plaster and thatportion of the teeth previously set in the wax base, and thenvulcanizing the rubber vulcan'ite.

5. The method of constructing dentures which includes mounting the teethupon an initial wax base, covering the mounted teeth and base with fluidplaster, subjecting the whole to heat in a dry oven to soften the waxand rigidly harden the plaster grippingly about the teeth, subjectingthe hardened plaster and teeth to a dry steam jet for blowing off thesoftened wax, packing rubber vulcanite on the hardened plaster and aboutthe teeth, and vulcanizing the rubber vulcanite to form the final basefor the teeth.

6. The method of constructing dentures which includes mounting the teethupon an initial wax base, covering the teeth and base with fluidplaster, subjecting the whole to heat in a dry oven to soften the waxand rigidly harden the plaster grippingly about the teeth, the hardenedplaster then functioning as an intermediate base for the teeth, blowingoff the softened Wax from the intermediate base and teeth, packingrubber vulcanite upon the intermediate base and about the teeth,reheating the Whole while subjecting the rubber vuleanite to compactingyielding pressure, and then vulczitnizing the rubber vulcanite to formthe final base for the teeth.

7. The method of constructing dentures which includesmounting theteeth-upon an initial wax base, disposing the teeth and base upon a hardplate and within a molding:- flask, covering the plaster wax-base andteeth with fluid plaster and then closing; the flask, subjecting theclosed flask to heat in a dry oven to soften the wax and rigidly hardenthe plaster grippingly about the teeth, the hardened plaster thenfunctioning an intermediate base for the teeth, opening the flask andblowing off the softened wax from the intermediate base and about theteeth, packing rubber vulcanite upon the intermediate base and about theteeth, again elos ing the flask andsubjecting the same to vulcanitecon'ipacting pressure, then subjecting the flask under yielding pressureto further heating to further compact the Vulcanite, and

then disposing the flask within a Vuleanizing apparatus for vuleanizingthe rubber vulcanite to form the final base for the teeth.

8. The method of constructing dentures which includes mounting the teethupon an initial Wax base, disposing the teeth and base upon a plate andwithin a molding flask, covering the plate, wax-base, and teeth withfluid plaster and then closing the flask, subjecting the closed flasktoheat in a dry oven to soften the wax and rigidly harden the plastergrippingly about the teeth, the hardened plaster then functioning as anintermediate base for the teeth, opening the flask and blowing oflj thesoftened war; from the intermediate base and the teeth. packing: rubbervulcanite upon the intcrlneiliate base and about the teeth, againclosing: the flask and subjecting the same to vulcanite con'ipactingpressure, then subjecting the flask under constant spring pressure todry heat to furthercompact the vulcanite, and then disposing the flaskWithin a vulcanizing apparatus for vulcanizing the rubber vulcanite toform the final base for the teeth.

In testimony whereof, I have signed my name to this specification.

JACOB C. SCHWARTZ.

